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I took Neil Armstrong's death personally. I was surprised to find myself so upset, honestly, since I knew so little about him: I had never seen him speak, never read his biography, and the Moon landings happened long before I was born. But, as I'm sure he would have understood, my grief wasn't really just about him. His death represented, to me, the end of an era, and the slow passing from living memory one of the most profound achievements of the human race.

I should perhaps provide some background. I'm a theoretical astrophysicist. I grew up in California and my career has carried me steadily east since then--I went to grad school at Princeton and I'm now a postdoc at Cambridge University. Soon, I'll be moving on to Melbourne, Australia, to take up a research fellowship there. I got into astrophysics because I love figuring things out, and because I've always been fascinated by the quest to understand the cosmos. But I also remember a moment, when I was a small child, that fundamentally changed my view of the world and my place in it. It was the first time I saw a photograph of the Earth from space. It was the first time I understood, beyond just hearing the words, that I lived on a *planet*. That my home was just one of many rocks, careening through space, and that there were real places, *out* *there*, where people could go. I can't say for sure, but the picture was probably this one, taken by the astronauts of Apollo 17, on their way to the Moon. The last time human beings would go there.

This is a photograph that couldn't have been taken by a satellite or from low-Earth orbit. It couldn't be taken today. The perspective of Earth from afar is one that we have lost. And one of the very few human beings to have personally experienced that perspective has now been lost to us, too.

When I was growing up, knowing I wanted to be a scientist, my grandfather was the person I most idolized. Like Armstrong, he had a quiet dignity and a fundamentally scientific outlook. He was also talked about in similar terms--as a man of great integrity, humility, and responsibility. Granddad had been a meteorologist in the Navy during World War II, and as part of his training he took courses at the California Institute of Technology--a place that seemed to me, as a teenager, to be a paradise of scientific discovery and rampant, celebrated geekiness. Granddad used to tell me stories of how his fellow Navy men tried to challenge the Caltech undergrads at poker and lost their shirts every time. He'd tell me about the pranks and traditions and feats of cleverness that abounded at Caltech in the 1940s. When I eventually attended Caltech as an undergrad, it was with the intention of making my grandfather proud, and with the additional thrill of sharing a special kinship with him.

After the war, my grandfather travelled all over the world with the Navy, so he had a lot of stories. But there was only one that I made him tell again and again: the one in which he worked with NASA and saved the mission, and the crew, of Apollo 11.

As a meteorologist, my grandfather's job for Apollo 11 was to check for weather problems around the capsule's splashdown site at the conclusion of the return trip. When the time came, he consulted all the data NASA had available and it looked okay. But he wanted to be sure. His previous assignment, in the Navy, had given him access to data from secret spy satellites, a product of the Cold War, and a project no one at NASA had clearance to know about. With just 72 hours to splashdown, he went to a nearby read-out station.

As soon as my grandfather arrived, Air Force Major Hank Brandli dragged him into his office and told him he'd seen "screaming eagle" thunderclouds forming in the satellite images. Brandli knew about NASA's intended splashdown site, but was forbidden to let on that the satellites existed, much less share any information with other agencies. And now my grandfather was in the same position. The capsule had to be rerouted or Armstrong, Aldrin and Collins would die, but no one could be told the reason for the change.

It was then up to my grandfather, alone, to convince NASA that there was a storm building at the splashdown site, without providing any proof or corroborating data. The satellite program's existence had to be kept secret, even from other government agencies. He had to rely only on his reputation as a trusted Navy man and a respected scientist. Thankfully, my grandfather's commanding officer agreed to take him at his word, and alerted Mission Control to reroute the capsule to a safe location and move the recovery team. But at the same time, the military also commanded a plane to fly out to the original site, just to check that the storm was really there. My grandfather was warned: he'd better be right. The new coordinates were sent, the capsule came down without incident, and the reconnaissance plane flew into weather so rough that the capsule's parachutes would certainly have been ripped to shreds. The astronauts were safe and so was my grandfather's career. He would even be awarded the Navy Commendation Medal when the program was declassified in the 1990s.

The more I learn about the Apollo program, the more I appreciate how much of it was a seat-of-the-pants effort, built on untested technology, driven by human ingenuity and tinged with more than a little hubris. As Apollo astronaut Jim Lovell said, "We just decided to go." The Moon landings weren't miraculous, or fated. They weren't convenient. They were incredibly dangerous and by no means guaranteed to end in success. But we did it. We went there. And I say "we" because that journey, perhaps more than any other in history, was a journey of humanity as a whole. Our *species* advanced. From that momentous day in 1969, we were no longer confined to the Earth; we could venture out, *in* *person*, and walk upon other worlds.

Don't get me wrong; I'm a big believer in robotic space exploration. As a scientist, I understand that it can, and does, offer us incredible insights into the formation of the Solar System, the history of life on Earth, and the environmental conditions of other planets and moons. I understand that robotic exploration is cheaper and safer than human spaceflight, and I understand that there are places robots can explore that no human being could ever survive.

But the Apollo program wasn't about science. It wasn't about doing anything cheaply or safely. It wasn't about what we would learn by bringing samples back from the Moon, or even about all the technological advances that came out of it. It was, fundamentally, about wonder. It was about expanding our horizons as a species and setting foot on a new world. It was about reaching out into the cosmos, being viscerally connected to it, and bringing that experience back to share with all who have looked up to the stars with a sense of awe and anticipation. It was about the recognition that we are all part of one human race, all living together on a tiny blue marble in the great black void. It was about heroes, like Neil Armstrong. And like my grandfather, too.

My grandfather passed away in January at the age of 88. Before he died, I visited him in the hospital to say goodbye, and to tell him I've applied to NASA's astronaut program. I haven't heard yet whether I'll be selected, though about a month ago I found out that I've made the first cut. I still want to make him proud.

Whether or not I ever go into space myself, I hope that we, as a nation and as a species, don't give up on human space exploration beyond low-Earth orbit. The Moon is so close. Mars is just next-door. Orbiters and rovers will continue to bring us tremendously valuable images and information, but I hope we remember the value of actually going there--the way it can change our perspective and make us, fundamentally, greater.

Neil Armstrong knew what it felt like to walk on another world. That experience will soon pass out of living memory entirely. But the footprints on the Moon will remain. And I hope others will follow them, soon, and walk farther.

Katie, Thank you so much for sharing your grandfather's story with us-- and for reminding us that there are many unsung heroes behind such missions. Good luck with your own application to become an astronaut!

And if we create a spaceship ? like that ,all people are happy.We could all discover this universal sphere and its spheres and its lifes:) it is one of my dream.

ps my favorite films, of course, avatar, starwars(oh my god, if you knew how I was fascinated by these films. The return of the jedi mainly :), startrek also)

It is frustrating to know the immensity of our universe and our technology in fact.

The future is to travel inside this universal sphere. We are travellers from stars.Starwalkers in fact. I am persuaded that at this present it exists so many planets with lifes. I d say even that it exists a number very very important of planets with lifes.

In fact we must create spaceships, in orbit firstly. It is even an priority for the humanity.

Ps I agree about Neil Amstrong, this mission was an incredible success for humanity.

Lovely article - I'm not a scientist myself but a historian and writer of science fiction, and have found the pictures coming back from Mars very exciting for just the reasons you describe. I also hope one day people really will walk there!

this is a very nice and quite personal article. I was only a young child during the Apollo missions. My enduring memory is of being fearful for the safety of all of the astronauts from the final countdown till the moments in which they emerged safely from the capsule after splashdown. I was particularly worried, every time, that they would be cooked alive upon re-entry and be found dead. Neil Armstrong and fellow astronauts were brave men. The repeated anxiety of watching those early space missions certainly gave me no desire to ever put myself in that situation. I wish you good luck with your ambition nonetheless and hope that you too will be safe.

Your article really inspired the explorer in me! Neil Armstrong, Buzz Aldrin and Michael Collins took that first giant leap to the moon in 1969. It's humanity's duty to now follow-up with many more giant steps. We'll start with other planets and moons in this solar system. But it's our nature to then go further and further - to the stars, to the other galaxies ... and these things will lead us to...

Your article really inspired the explorer in me! Neil Armstrong, Buzz Aldrin and Michael Collins took that first giant leap to the moon in 1969. It's humanity's duty to now follow-up with many more giant steps. We'll start with other planets and moons in this solar system. But it's our nature to then go further and further - to the stars, to the other galaxies ... and these things will lead us to trips into the future and the past. All this might seem impossible today, but below I'm daring to dream (guided by modern science) - and I'm hoping all these scientific miracles are achieved in time for the centenary of the moon landing on July 20, 2069.

Maybe hidden variables called binary digits (binary digits would be the hidden variables which Einstein said carry extra information about the world of quantum mechanics … and complete it, eliminating probabilities and bringing about exact predictions) could permit time travel into the future by warping positive space-time. And maybe they'd allow time travel into the past by warping a 5D hyperspace # that is translated 180 degrees to space-time, and could be labelled as negative or inverted. (The space-time we live in is described by ordinary [or “real”] numbers which, when multiplied by themselves, result in positive numbers e.g. 2x2=4, and -2x-2 also equals 4. Inverted “positive” space-time becomes negative hyperspace which is described by so-called imaginary numbers that give negative results when multiplied by themselves e.g. i multiplied by itself gives -1.) The past can never be changed from what occurred, and the future can never be altered from what it will be. Both are programmed by the 1’s and 0’s.

# This 5th-dimensional hyperspace would be tinier than a subatomic particle, like the dimensions invoked by string theory (about 70% of space consists of dark energy, according to the WMAP and Planck space probes – which is interpreted in this article as 70% of a particle also consisting of dark energy since “space-time itself plays a role in the constitution of elementary particles and the nuclear forces” (see paragraph in http://vixra.org/abs/1307.0072 about Einstein’s 1919 submission to the Prussian Academy of Sciences). This dark energy can be associated with hyperspace and its binary digits because that article mentioned in the previous sentence states that binary digits produce space-time, via modification of string theory. So a) 70% of a particle is composed of hyperspace, and b) the extra dimension exists everywhere in space occupied by particles (also everywhere in “empty” space, where binary digits are referred to as Virtual Particles). With a single extra dimension of astronomical size, gravity is expected to cause the solar system to collapse (“The hierarchy problem and new dimensions at a millimetre” by N. Arkani-Hamed, S. Dimopoulos, G. Dvali - Physics Letters B - Volume 429, Issues 3–4, 18 June 1998, Pages 263–272, and “Gravity in large extra dimensions” by U.S. Department of Energy - http://www.eurekalert.org/features/doe/2001-10/dbnl-gil053102.php However, collapse never occurs if gravity accounts for repulsion as well as attraction on both subatomic and astronomical scales (accounts for dark energy and familiar concepts of gravity, as well as repelling aspects of the electroweak force [such as placing two like magnetic poles together] and attracting electroweak/strong force aspects). “Electroweak” and “strong” force can be united in that sentence because gravitation and space-time are united with both the (electro)weak and strong nuclear forces.

The inverse-square law states that the force between two particles becomes infinite if the distance of separation between them goes to zero. Remembering that gravitation (associated with particles) partly depends on the distance between their centres, the distance of separation only goes to zero when those centres occupy the same space-time coordinates (not merely when the particles’ or objects’ sides are touching i.e. infinity equals the total elimination of distance^). The infinite cosmos could possess this absence of distance in space and time, via the electronic mechanism of binary digits (this would enable it to be as malleable and flexible as anything on a computer screen). To distinguish this definition from “the universe going on and on forever”, we can call it “electronic infinity or e infinity”.

^ If infinity (not physical infinity, but e infinity) is the total elimination of distance in space-time, there would be nothing to prevent instant intergalactic travel or time travel to the past and future^^. Infinity does not equal nothing - total elimination of distance, or space-time, produces nothing in a physical sense and reverts to theoretical physicist Lee Smolin’s imagining of strings as “not made of anything at all” (p.35 of Dr. Sten Odenwald’s article “What String Theory Tells Us About the Universe”: Astronomy – April 2013). It also reverts the universe to the mathematical blueprint from which physical being is constructed (see http://vixra.org/abs/1307.0072 – this agrees with cosmologist Max Tegmark’s hypothesis that mathematical formulas create reality, http://discovermagazine.com/2008/jul/16-is-the-universe-actually-made-of-math#.UZsHDaIwebs and http://arxiv.org/abs/0704.0646). So, infinity = something, agreeing with Dr. Sten Odenwald’s statement on p.32 of his article, that “The basic idea is that every particle of matter … and every particle that transmits a force … is actually a small one-dimensional loop of something.

Here’s a proposed method for making time travel to the past practical – In July 2009, electrical engineer Hong Tang and his team at Yale University in the USA demonstrated that, on silicon chip-and transistor-scales, light can attract and repel itself like electric charges/magnets. This is the “optical force”, a phenomenon that theorists first predicted in 2005 (this time delay is rather confusing since James Clerk Maxwell showed that light is an electromagnetic disturbance approx. 150 years ago). In the event of the universe having an underlying electronic foundation, it would be composed of "silicon chip-and transistor-scales” and the Optical Force would not be restricted to microscopic scales but could operate universally. Tang proposes that the optical force could be exploited in telecommunications. For example, switches based on the optical force could be used to speed up the routing of light signals in fibre-optic cables, and optical oscillators could improve cell phone signal processing. From 1929 until his death in 1955, Einstein worked on his Unified Field Theory with the aim of uniting electromagnetism (light is one form of this) and gravitation. Achievement of this means warps of space (gravity, according to General Relativity) between spaceships/stars could mimic the Optical Effect and could be attracted together, thereby eliminating distance (similar to traversing a wormhole between two folds in space). And "warp drive" would not only come to life in future science/technology ... it would be improved tremendously; even allowing literally instant travel to points many, many billions of light years away. This reminds me of the 1994 proposal by Mexican physicist Miguel Alcubierre of a method of stretching space in a wave which would in theory cause the fabric of space ahead of a spacecraft to contract and the space behind it to expand - Alcubierre, Miguel (1994). "The warp drive: hyper-fast travel within general relativity". Classical and Quantum Gravity 11 (5): L73–L77. Therefore, the ship would be carried along in a warp bubble like a person being transported on an escalator, reaching its destination faster than a light beam restricted to travelling outside the warp bubble. There are no practical known methods to warp space – however, this extension of the Yale demonstration in electrical engineering may provide one. (And if infinity is the total elimination of distance in space-time, there would be nothing to prevent time travel to the past and future.)

I'm so sorry about Neil Armstrong's death, too. I feel as though I knew him, but I never had any contact with him. However, I think he's still alive - in a different form, somewhere in the universe ... somewhere in time. After all, science's Law of Conservation has known since the 19th century that neither matter nor energy (including the matter/energy of the first person on the moon) can ever be destroyed or created - they only change form, as in the death and birth of a man named Armstrong. If we stop thinking at that point, we'd assume that at death, his body became disorganized and returned to dust - and that his mind simply ceased to exist when his brain became dust. But let's keep thinking. If nothing in any time can be destroyed, all time must be like a DVD. All of the DVD always exists even though a very limited set of sights and sounds can be perceived at any point during its playing. Similarly, Neil always exists even though we can't physically perceive him at this time. In different parts of the cosmic DVD; he's forever being born, forever taking that first step on the moon, forever resting in peace, and I think medical science will someday advance so much (and in such unexpected ways) that we'll be able to say he's forever being resurrected (I believe English physicist Julian Barbour has the same understanding of time which this sentence speaks of). How could the time travel loved by theoretical physicists come to pass without this "cosmic DVD"? (see the posting I put on this page earlier this afternoon for possible details about achieving time travel - to the past as well as the future).